JPH06269142A - Spindle motor and its assembly method - Google Patents

Abstract

PURPOSE:To adopt a dynamic-pressure fluid bearing mechanism wherein a spindle motor is provided with excellent characteristics such as a simple structure, low costs, a small size, a low power consumption, a low noise and the like by obtaining an air discharge structure problems such as the avoidance of the blockade of the air, the discharge of air bubbles and the prevention of the contamination of an apparatus in the assembly of the dynamic-pressure fluid bearing mechanism is solved. CONSTITUTION:A communication groove 23b is formed at the outer circumferential side of a sleeve metal 21 constituting a dynamic-pressure fluid bearing mechanism, i.e., at the inner circumference of a housing 23a. Thereby, when a lubricative fluid in a proper amount is injected into the inside of a lower assembly 20 and the free end of a shaft 12 at an upper assembly 15 is inserted, the air at the inside is not confined and can be discharged, and an assembly operation can be performed smoothly. When the shaft 12 is inserted, there may be a fear that the lubricative fluid together with the air is discharged form the communication groove 23b. As a result, a space in which the fluid is stored is formed on the side of an opening edge 21 a so that the lubricative fluid is not scattered and lost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a spindle motor of a disk drive device used mainly in the information processing field.

[0002]

2. Description of the Related Art In recent years, the size and density of disk drive devices (hereinafter referred to as devices) have been increasing. Of these types of devices, those that place importance on portability are often required to have particularly small size, impact resistance, low noise, and low power consumption. Among them, of course, there is a similar demand for a spindle motor (hereinafter, abbreviated as a motor) that drives a disk to rotate.

One of the key components that determines these performances is a motor bearing. Conventionally, a ball bearing has been generally used as a bearing, but a hydrodynamic bearing has been attracting attention and being adopted as a bearing that can meet the above-mentioned demand at a higher level. What is a hydrodynamic bearing?
It is composed of a cylindrical shaft and a hollow cylindrical sleeve metal fitted with a gap therebetween, and a herringbone groove or the like is provided in either of them. The clearance is filled with a lubricating fluid (often oil or grease), and the rotor is supported by the pressure generated in the fluid as the rotor rotates. In principle, the volume occupied by the mechanism is small, the rotation noise is low and the shock resistance is excellent because the rotor is supported via fluid, and the shaft run-out is reduced due to the integral effect because the load is applied on the entire circumference of the shaft. Excellent as a bearing for this device. However, since the features described here relate to the radial bearing and do not have the ability to support the load in the thrust direction, another dedicated bearing is provided in the thrust direction.

There are various structures for the thrust bearing, but the structure that is simple and is often used is that it is composed of the shaft tip and the thrust plate facing it. There are those that are pivot-shaped and those that form a spiral groove to generate dynamic pressure. Thrust bearings are often arranged on one end surface of the radial bearing.

[0005]

Since it is desired that the device be as small and thin as possible, the axial height of the motor is also limited. On the other hand, it is needless to say that the axial height of the radial bearing is large, so it is desirable to reduce the height occupied by the thrust bearing. In order to meet this demand, when fixing the thrust plate to the end surface of the sleeve metal, it is not a method such as screw tightening that tends to increase the height, but crimping, press-fitting, adhering, integrating the sleeve metal and the thrust plate A structure that requires only a small height, such as being formed in the above-mentioned structure, is adopted. In this construction, the thrust plate generally must be preassembled on the sleeve end face prior to inserting the shaft into the bearing. This is because it is difficult to support the load applied to the component and maintain the position even if the thrust plate is attached after inserting the shaft.

Such a hydrodynamic bearing mechanism has a problem to be solved when assembling the motor.
This is because if a lubricating fluid such as oil is previously supplied to the inside of the bearing and then the shaft is inserted, the air inside the bearing is blocked because the end face is closed by the thrust plate, which makes it extremely difficult to insert the shaft. Assembly of the motor is virtually impossible unless means are provided to avoid this space blockage problem.

What must be considered next is a countermeasure against bubbles generated in the lubricating fluid during motor operation.
The hydrodynamic bearing supports the rotor by the pressure generated by the rotation, but at this time, it may become a burden depending on the position or operating conditions, and bubbles may occur there. When air bubbles are generated in the bearing support portion, the load supporting ability of that portion is reduced, which lowers the rotation accuracy and the lubrication ability of the rotor and eventually the service life. Therefore, this bubble needs to be discharged from the bearing portion to the outside.

In order to solve these problems, the present invention proposes a mechanism for discharging the air from the bearing, but side effects of the mechanism, that is, contamination and depletion due to leakage of the lubricating fluid from the discharge mechanism occur. It is necessary to consider not to do so. In the magnetic disk device, which is the main application of this motor, the medium is required to be in an extremely clean space. That is, it is desired to prevent contaminant particles outside the apparatus from flowing into the clean space inside the apparatus from this air discharge mechanism. Although a proposal of an air discharge mechanism has already been proposed in U.S. Pat. No. 4,557,610, this does not include a concept of actively preventing device contamination.

As described above, the present invention mainly focuses on a thin motor used in a magnetic disk drive, and solves the air discharge problem associated with a hydrodynamic bearing mechanism for a thin motor, that is, air blockage during assembly. There is provided an air discharge structure capable of solving all or any one of the three problems of avoiding air pollution, discharging air bubbles, and preventing device contamination. And by doing so, the spindle motor has a simple structure,
An object of the present invention is to make it possible to employ a hydrodynamic bearing mechanism having excellent features such as low price, small size, thin thickness, low power consumption, and low noise.

[0010]

The present invention provides various means for solving the above problems. The first group communicates the space near the thrust bearing with the end surface of the sleeve on the open end side. More specifically, the sleeve metal is provided with a through hole parallel to the axis to communicate with the opening end, the sleeve metal is communicated with a gap between the sleeve metal and the housing on the outer periphery thereof, and the sleeve metal is 2 A piece of herringbone grooved liner with a gap between it and the housing on its outer circumference.
For example, a vertical groove is provided between the inner peripheral surface of the sleeve and the shaft for communication, or one of the herringbone grooves is formed deeper than the other to be used as a communication groove.

Further, the end face of the sleeve on the open end side stores a lubricating fluid discharged together with air, has an oil reservoir space for trapping foreign matters to continue lubrication and prevent device contamination, and further prevents fluid leakage. Therefore, a filter made of an oil-repellent material or a material that allows gas molecules to selectively pass therethrough is installed.

The second group is to inject a lubricating fluid into the bearing after inserting the shaft in order to prevent air blockage due to the presence of fluid in the bearing clearance. The central theme of this type is how to fill the bearing space with lubricating fluid after shaft insertion. First,
In order to store the lubricating fluid to be injected, a fluid holding space having a volume sufficient to fill the bearing space is provided near the end surface on the open end side of the sleeve. The space may be filled with oil in advance before inserting the shaft, or may be injected later from the outside of the motor. Then, after inserting the shaft, the motor is evacuated to replace the air and oil in the bearing space, heated to lower the viscosity and wetting angle to allow the oil to enter the bearing space, and tilted to make contact with the shaft by capillary action. The fluid held in the space is infiltrated and filled into the bearing space by using a means such as permeating into the bearing clearance. Further, the fluid filling method using negative pressure or the like may be applied to the bearing having the air discharge groove described in the first group.

When looking at the appearance of the motor, it is difficult to make a clear difference between the motor to which this assembly method is applied and the motor to which this assembly method is not applied. However, a member fixed to one end of the shaft, such as a hub, may have holes or dents. The characteristic feature is that a lubricating fluid can be supplied to the sleeve metal opening end surface, or a sufficient amount of fluid can be stored in the sleeve opening end surface.

The third group is one in which a vertical hole is formed in the shaft to connect the thrust bearing space with the outside of the bearing.
This hole is preferably provided in a portion of the thrust bearing space where the fluid pressure during rotation is low, for example, on the outer peripheral side, avoiding the central axis of the shaft. Further, if a filter that allows only air to pass is provided on the side of the hole near the outside of the bearing, leakage of the lubricating fluid from the air discharge hole can be prevented.

Further, the fourth group is provided with a hole for discharging air in the bearing space on the thrust plate side, and a filter is also used to prevent the fluid from leaking from the hole. The filter may be provided in the hole or may be arranged so as to cover the hole from the outside of the thrust plate. Further, this air discharge hole is preferably provided at a portion where the fluid pressure is low, in many cases, at a position avoiding the central axis, as in the above description.

Here, terms and expressions used in the specification will be described. The sleeve metal is a bearing cylinder that supports the radial load of the shaft, and a copper alloy is generally suitable, but is not limited to a metal material. The herringbone groove may be formed on any of the sleeve metal shafts. The thrust plate is a member that faces the end surface of the shaft and supports a thrust load. Since motors that are required to be thin will naturally use plate-shaped members, this expression is used for easy understanding. However, depending on the required specifications and the surrounding structure, there are cases where a shape called by another expression such as a block shape or a cup shape is selected. The same applies to the air discharge groove / hole. In the text, vertical grooves and holes parallel to the axis are used for easy understanding, but other shapes such as spiral shape may be used depending on the processing requirements. When the groove is provided between two adjacent members, the air communication function is the same regardless of which member is formed, which is within the scope of the present invention.

[0017]

In the first group, the air in the bearing space is communicated with the end surface of the sleeve metal opening and discharged. In this structure, the air discharge hole is directed to the inside of the motor, and the inside and outside of the device are not communicated. Therefore, since the air inside and outside the device does not flow, the air can be discharged while preventing the inside of the device from being contaminated by the outside air. Therefore, it is most suitable for a disk device that requires cleanliness.

The second group is to fit the shaft and the sleeve together without oil in order to avoid difficulty in inserting the shaft due to air blockage. This type is also used when it is not necessary to give special consideration to the discharge of bubbles during operation. The main feature is that the bearing can be assembled in a dry state, and since there is no air blockage, the shaft can be easily inserted and assembled.

The third group discharges bubbles in the bearing space to the outside of the motor through the shaft, and the fourth group discharges bubbles from the thrust plate side. In either case, whether or not the communication hole communicates with the outside of the device depends on whether the shaft is designed to rotate or is arranged on the fixed side. In the case of no communication, it has characteristics similar to those of the first group, but it is desirable to use a filter together because fluid may leak into the device. Even when communicating with the outside of the device, the use of a filter can prevent contamination of the outside of the device. Further, the mechanism of these groups can also take a method of injecting a lubricating fluid through the communication hole after the shaft is inserted and the assembly of the motor is completed.

As described above, the above-mentioned problems can be effectively solved by selecting and adopting some of the air discharge mechanisms described here in accordance with the device required specifications.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the motor together with a part of the periphery of the device. This corresponds to the above-mentioned first group. The motor is fixed to the base 102 of the apparatus by a screw 101, and a screw 105 and a clamp ring 104 are used to mount a disk 105 for rotational driving.

First, the structure is reviewed from the viewpoint of function. The shaft 1 is located at the center of the hub 11 on which the disc 105 is mounted.
2 is attached and rotates with the hub 11 and the disk 105 to form the center of rotation. The shaft 12 is supported by the sleeve metal 21 in the radial direction, and the thrust plate 22
It is supported in the thrust direction. A lubricating fluid, such as oil, is filled between the shaft 12 and the sleeve metal 21, and between the shaft 12 and the thrust plate 22, respectively.
A herringbone groove 12a is formed in the shaft 12, and when the shaft 12 rotates, pressure is generated in the lubricating fluid to form a hydrodynamic bearing mechanism. On the other hand, the shaft end surface 12b and the thrust plate 22 constitute a thrust bearing mechanism while preventing wear by the lubricating fluid filled between them.

The rotational driving force of the motor is the stator coil 2
5 is generated by the rotating magnetic field created by the stator core 24 which is wound by winding 5 and excited by power supply, and the multi-pole magnetized drive magnet 14 surrounding it. The drive magnet 14 is fixed to the inner circumference of the rotor frame 13,
3 is fixed to the hub 11 at its inner circumference and constitutes the rotor 10 as a whole and rotates. The stator core 24 is fixed to the bracket 23 and serves as a driving force generation source.

Next, the procedure for assembling this motor will be described. Among the components that make up the stator, the stator core 24 on which the stator coil 25 is wound in advance is attached to the bracket 2
Fix to 3. Then, the sleeve metal 21 is fitted and fixed to the cylinder 23a at the center of the bracket 23 (hereinafter, this portion is referred to as a housing). Then, the thrust plate 22 is fixed to the lower end surface of the housing 23a by means such as caulking to complete the lower assembly 20.

Of the parts constituting the rotor 10, the shaft 12 is firmly fixed at its one end to the central hole of the hub 11 by means of shrink fitting or the like. Then, the holes on the inner circumference of the rotor frame 13 and the corresponding locking projections of the hub 11 are fitted together and firmly fixed by means such as caulking.
Further, the drive magnet 14 is fixed to the inside of the rotor frame 13 by means such as adhesion. After that, the cap 26 is inserted from the free end side of the shaft 12 and fitted into the position of the locking groove 12c at the innermost side, whereby the upper assembly 15 is completed.

Next, an appropriate amount of lubricating fluid is injected inside the sleeve metal 21 of the lower assembly 20,
Insert the free end of the shaft 12 of the upper assembly 15. At this time, since the cap 26 has a size with a tightening margin with respect to the outer periphery of the housing 23a, a push rod (not shown) is inserted through the three small holes 11a formed in the hub 11, and the cap 26 Housing 2
Push in until it contacts the end face of 3a. In this way, the assembly of the motor is completed.

Here, a communication groove 23b is provided on the outer peripheral side of the sleeve metal 21, that is, on the inner peripheral side of the housing 23a. Due to the existence of the communication groove 23b, the shaft 1
When 2 is inserted into the sleeve metal 21, the internal air can be discharged without being trapped, so that a smooth assembly is possible. Further, when the shaft 12 is inserted, the lubricating fluid may be discharged together with the air from the communication groove 23b, so that a space for storing the fluid is provided on the opening end face side 21a so as not to dissipate the lubricating fluid.

(Embodiment 2) FIG. 2 shows an example in which a communication hole is formed in the sleeve metal itself.

Illustration is omitted except for the bearing mechanism. A through hole 27a is formed in the sleeve metal 27 in parallel with its central axis, and a thrust plate 22 is fixed to one end surface of the sleeve metal 27 to support the shaft 16. And sleeve metal 2
The inner surface of 7 and its through hole 27 a communicate with each other near the thrust plate 22.

(Embodiment 3) FIG. 3 shows an example in which the sleeve metal is divided into two.

The communication grooves 29a and 30a are formed on the outer circumferences of the two sleeve metals 29 and 30 attached to the housing 28. According to this structure, not only the space in the vicinity of the thrust bearing but also the space between the two radial dynamic pressure generating portions can communicate with the outside air. Further, in this example, the filter 31 on the opening end face side of the sleeve metal 29 is
Are arranged. By this filter 31, it is possible to prevent the dissipation of the lubricating fluid from the communication hole while discharging the air.

(Embodiment 4) FIG. 4 is an example in which the inner diameter side of the sleeve metal is communicated with the outside air.

The inner diameter of the sleeve metal 32 has a vertical groove 32a which communicates both ends with a part of the circumference, so that the air in the vicinity of the thrust bearing is discharged to the open end side. This vertical groove 32
Although a may be located on either the shaft side or the sleeve metal side, it is desirable to provide a on the softer material from the viewpoint of life.

(Embodiment 5) FIG. 5 shows an example in which a herringbone groove is used as an air discharge groove.

In this case, the groove 33a is formed on the inner diameter side of the sleeve metal 33. One of the herringbone grooves 33b is made deeper than the other grooves so that air can easily pass therethrough, thereby connecting the space of the thrust bearing portion and the opening end face side.

(Embodiment 6) Although FIG. 6 is not directly related to air discharge, the amount of lubricating fluid stored around the thrust bearing is increased to further extend the life of the bearing. The thrust plate 22 is attached to one end of the housing 34, and the sleeve metal 35 is fixed to the inner diameter side. A cylindrical space 34a is provided in the vicinity of the thrust bearing between the sleeve metal 35 and the housing 34 so that the lubricating fluid can be stored.

(Embodiment 7) Next, a second group, that is, an example in which a lubricating fluid is supplied after the shaft is inserted without having an active air discharge mechanism will be described. FIG. 7 shows the motor structure. It is similar to that shown in FIG. 1, but differs in its lubricating fluid injection procedure.

The procedure for assembling the lower assembly 40 is shown in FIG.
However, the parts and the shape of the bracket 43 are partially different. The bracket 43 has a larger fluid holding space above the housing portion 43a. Also,
There is no air exhaust groove. Upper assembly 15
1 is the same as that shown in FIG.

When both the assemblies are completed, the free end of the shaft 12 of the upper assembly 15 is inserted into the sleeve metal 41 of the lower assembly 40. At this time, as in the case of the first embodiment, the cap 26 inserts a push rod (not shown) through the three small holes 11a formed in the hub 11 until the cap 26 comes into contact with the end surface of the housing portion 43a. Push in. And the small hole 1 of the hub 11
1a from the required amount of lubricating fluid sleeve metal end surface 41a
Supply to. After that, when the motor is placed in a negative pressure environment and returned to atmospheric pressure again, the air in the bearing space is replaced with the lubricating fluid.
In this way, the assembly of the motor is completed.

Here, the lubricating fluid may be supplied to the sleeve metal end surface 41a before inserting the upper assembly 15. Further, in order to fill the bearing space with the lubricating fluid, a method of increasing the ambient temperature to reduce the viscosity and causing the lubricating fluid to enter the bearing clearance by the capillary phenomenon may be used.

(Embodiment 8) FIG. 8 shows an example of a third group in which air is discharged through a shaft.

A through hole 17a-1 is formed in the center of the shaft 17.
7b, which connects the thrust bearing space and the external space. The through hole 17b is provided on the thrust bearing side while avoiding the central portion of the shaft. A filter 18 is attached to the other end to prevent fluid from leaking and contaminating the inside and outside of the device.

(Embodiment 9) FIG. 9 shows an example in which air is discharged to the thrust plate side of the fourth group.

Since the lubricating fluid may leak out simply by providing the vent hole 46a in the thrust plate 46, the filter 47 is used to prevent it. In this case, the filter 47 is installed between the end surface of the sleeve 45 and the thrust plate 46 so as to close the ventilation hole 46a.

In the above, only the shaft rotation type structure is shown so as not to obscure the understanding by complicating the description. The thrust bearing mechanism has been described with the simplest structure. The structure is also described in a unified manner without any variety. Therefore, the present invention is limited to a limited range, but the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present invention.

[0047]

As is apparent from the above embodiments, the present invention has three problems of air discharge problems associated with the hydrodynamic bearing mechanism, that is, avoidance of air blockage during assembly, discharge of air bubbles, and prevention of device contamination. Since several air discharge structures capable of solving the above have been provided, the aforementioned problems can be effectively solved by selecting and adopting them according to the device required specifications.
These structures exhibit superiority especially when applied to a thin disk drive motor in which the height occupied by the thrust bearing is reduced.

As described above, according to the present invention, it is possible to manufacture a motor which makes full use of the features of the hydrodynamic bearing having excellent low noise characteristics, high impact resistance, and high rotation accuracy in principle. It is possible to provide an excellent device that meets a request at low cost.

[Brief description of drawings]

FIG. 1A is a sectional view of a motor and a peripheral portion of a first embodiment. FIG. 1B is a plan view of a sleeve metal and a housing cut at an intermediate portion.

FIG. 2 (a) is a sectional view of the bearing mechanism of the second embodiment. FIG. 2 (b) is a plan view of the sleeve metal cut at an intermediate portion.

FIG. 3 (a) is a sectional view of the bearing mechanism of the third embodiment. FIG. 3 (b) is a plan view of the sleeve metal and the housing cut at an intermediate portion.

FIG. 4 (a) is a cross-sectional view of a bearing mechanism of a fourth embodiment. FIG. 4 (b) is a plan view of the sleeve metal cut at an intermediate portion.

FIG. 5 (a) is a sectional view of a bearing mechanism (excluding a shaft) of a fifth embodiment. FIG. 5 (b) is a plan view of the sleeve metal cut at an intermediate portion.

FIG. 6 (a) is a sectional view of a bearing mechanism of a sixth embodiment. FIG. 6 (b) is a plan view of the sleeve metal and housing cut near the lower part.

FIG. 7 (a) is a cross-sectional view of a motor and its peripheral portion according to a seventh embodiment.

FIG. 8 is a sectional view of a bearing mechanism of an eighth embodiment.

FIG. 9 is a sectional view of a bearing mechanism according to a ninth embodiment.

[Explanation of symbols]

10 rotor 11 hub 11a small hole 12, 16, 17 shaft 12a herringbone groove 12b shaft end face 12c locking groove 13 rotor frame 14 drive magnet 15 upper assembly 17a, 17b, 27a through hole 18, 31, 47 filter 20, 40 lower assembly 21, 27, 29, 30, 32, 33, 35, 41 Sleeve metal 21a Opening end face side 22, 46 Thrust plate 23, 43 Bracket 23a, 28, 34 Housing 23b, 29a, 30a Communication groove 24 Stator core 25 Stator coil 26 Cap 32a Vertical groove 33a, 33b Groove 34a Space 41a Sleeve metal end surface 43a Housing part 45 Sleeve 46a Vent hole 101, 103 Screw 102 Base 104 Clamp ring 10 5 discs

Claims (17)

[Claims] 1. A rotor having a disk mounted thereon and rotating, a hydrodynamic radial bearing for supporting the rotor in a radial direction, a thrust bearing for supporting the rotor in a thrust direction, and a drive mechanism for rotationally driving the rotor. The radial bearing includes a shaft, a sleeve metal, and a lubricating fluid, the thrust bearing includes an end surface of the shaft, a thrust plate, and a lubricating fluid that are closely adjacent to each other, and the thrust plate is provided on one end surface side of the sleeve metal. And a space near the thrust bearing and the opening end face side of the sleeve metal communicate with each other. 2. The spindle motor according to claim 1, wherein a space provided in the vicinity of the thrust bearing communicates with the end surface side of the sleeve metal opening through a hole provided in the sleeve metal. 3. The sleeve metal is mounted and supported on a housing on an outer peripheral side thereof, and a groove provided between the sleeve metal and the housing forms a space near the thrust bearing and an opening end surface of the sleeve metal. The spindle motor according to claim 1, wherein the spindle motor is structured to communicate with the side. 4. Two sleeve metals are mounted and supported on a housing on the outer peripheral side thereof, and a groove provided between the two sleeve metals and the housing forms a space near the thrust bearing and the space. The spindle motor according to claim 1, wherein the spindle metal has a structure in which the sleeve metal communicates with the opening end face side. 5. The spindle motor according to claim 1, wherein the vertical groove provided on the inner diameter side of the sleeve metal allows the space near the thrust bearing to communicate with the opening end face side of the sleeve metal. 6. One of the dynamic pressure generating grooves of the sleeve metal is formed deeper than the other grooves, and the groove allows communication between the space near the thrust bearing and the opening end face side of the sleeve metal. The spindle motor according to claim 1. 7. The spindle motor according to claim 1, wherein a space for storing a lubricating fluid is provided on the opening end face side of the sleeve metal. 8. The spindle motor according to claim 1, wherein a space for storing a lubricating fluid is provided between the sleeve metal side of the sleeve metal and a housing on an outer periphery thereof. 9. The spindle motor according to claim 1, wherein a filter made of an oil-repellent material or a material that allows gas molecules to selectively pass therethrough is arranged on the opening end surface side of the sleeve metal. 10. A rotor that mounts and rotates a disk,
It has a hydrodynamic radial bearing that supports the rotor in the radial direction, a thrust bearing that supports in the thrust direction, and a drive mechanism that rotationally drives the rotor, and the radial bearing includes a shaft, a sleeve metal, and a lubricating fluid. The thrust bearing includes an end surface of the shaft, a thrust plate, and a lubricating fluid, which face each other in close proximity to each other, and the thrust plate is disposed on one end surface side of the sleeve metal, and on the opening end surface side of the sleeve metal. Is a spindle motor that has a space to store sufficient lubricating fluid to fill the bearing space. 11. The spindle motor according to claim 10, wherein the member fixed to one end of the shaft has a small hole capable of supplying a lubricating fluid to the opening end face side of the sleeve metal. 12. A rotor that mounts and rotates a disk,
It has a hydrodynamic radial bearing that supports the rotor in the radial direction, a thrust bearing that supports in the thrust direction, and a drive mechanism that rotationally drives the rotor, and the radial bearing includes a shaft, a sleeve metal, and a lubricating fluid. The thrust bearing includes an end surface of the shaft, a thrust plate, and a lubricating fluid that are closely opposed to each other, the thrust plate is disposed on one end surface side of the sleeve metal, and the space on the opening end surface side of the sleeve metal is included. A spindle motor assembling method in which a lubricating fluid is stored, the sleeve metal and the shaft are fitted to each other, and then a negative pressure is applied to the bearing space to replace the air in the bearing space with the lubricating fluid. 13. A lubricating fluid is stored in a space on the side of the opening end surface of the sleeve metal, the sleeve metal and the shaft are fitted together, and then the lubricating fluid and its periphery are heated to reduce the viscosity and to be in the bearing space. Claim 1 to invade
2. A method of assembling a spindle motor according to 2. 14. A rotor having a disk mounted thereon and rotating,
It has a hydrodynamic radial bearing that supports the rotor in the radial direction, a thrust bearing that supports in the thrust direction, and a drive mechanism that rotationally drives the rotor, and the radial bearing includes a shaft, a sleeve metal, and a lubricating fluid. The thrust bearing includes an end surface of the shaft, a thrust plate, and a lubricating fluid that are closely opposed to each other, the thrust plate is disposed on one end surface side of the sleeve metal, and the shaft includes a vicinity of the thrust bearing. Spindle motor having a small hole that communicates the space of the shaft with the shaft end on the opposite side. 15. The spindle motor according to claim 14, wherein the opening hole on the thrust bearing surface side of the shaft is provided so as to be displaced from the center of the shaft. 16. The spindle motor according to claim 14, wherein a filter made of an oil repellent material or a material that allows gas molecules to selectively pass therethrough is loaded in the small hole provided in the shaft. 17. A rotor having a disk mounted thereon and rotating,
It has a hydrodynamic radial bearing that supports the rotor in the radial direction, a thrust bearing that supports in the thrust direction, and a drive mechanism that rotationally drives the rotor, and the radial bearing includes a shaft, a sleeve metal, and a lubricating fluid. The thrust bearing includes an end surface of the shaft, a thrust plate, and a lubricating fluid that are closely opposed to each other, the thrust plate is disposed on one end surface side of the sleeve metal, and the thrust plate has the thrust bearing. A spindle motor is provided with a hole that connects a nearby space and the outside, and is equipped with a filter made of a material that is oil-repellent or selectively allows gas molecules to pass through near the hole.